The infrared spectrum of DCCF in the 320–850 cm−1 region: bending states up to υ4+υ5 = 3

Infrared spectra of deuterated monofluoroacetylene, DCCF, have been recorded in the region between 320 and 850 cm−1 at an effective resolution ranging from 0.0024 to 0.0031 cm−1. In total, 6650 rotation vibration transitions were assigned to 37 bands involving the bending states with v4 + v5 and |l4+l5|, respectively, up to 3, allowing the characterisation of the ground state and of 18 vibrationally excited states. The vν5 bending fundamental has been studied for the first time. In addition, the difference band v3 ← v4 has been detected and analysed. All the assigned transitions have been fitted simultaneously by adopting a model Hamiltonian that takes into account the vibration and rotation l−type resonances. Rotational transitions in the ground and in bending excited states reported in the literature have been included in the global analysis. The set of 57 derived spectroscopic parameters reproduces 6130 infrared and 90 microwave and millimetre−wave transitions satisfactorily with root mean square value...